Integrating pytest's --stepwise with Django Tests

You're looking to use pytest's stepwise functionality with Django tests, which is a great approach for iterative debugging. While Django's default test runner is based on unittest, you can integrate pytest with Django to leverage features like the stepwise option.

Setting up pytest with Django

To use pytest with Django, you'll need to:

1. Install the required packages:

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pip install pytest pytest-django

2. Create a pytest.ini file in your project root:

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[pytest]
DJANGO_SETTINGS_MODULE = your_project.settings
python_files = test_*.py *_test.py tests.py

3. Create a custom test runner that uses pytest:

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# myapp/pytest_runner.py
from pytest_django.plugin import pytest_configure
import pytest

class PytestTestRunner:
    """Runs pytest to discover and run tests."""

    def __init__(self, verbosity=1, failfast=False, keepdb=False, **kwargs):
        self.verbosity = verbosity
        self.failfast = failfast
        self.keepdb = keepdb
        self.kwargs = kwargs

    def run_tests(self, test_labels):
        """Run pytest and return the exitcode."""
        argv = []
        
        if self.verbosity > 1:
            argv.append('-v')
        
        if self.failfast:
            argv.append('--exitfirst')
            
        if self.keepdb:
            argv.append('--reuse-db')
            
        # Add stepwise option
        argv.append('--stepwise')
        
        argv.extend(test_labels)
        
        return pytest.main(argv)

4. Update your Django settings to use this custom test runner:

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# settings.py
TEST_RUNNER = 'myapp.pytest_runner.PytestTestRunner'

Alternative Approach: Direct pytest Command

If you prefer not to modify your Django settings, you can run pytest directly:

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pytest --ds=your_project.settings --stepwise

This command tells pytest to use your Django settings and enables the stepwise option.

Creating a Wrapper Script

For a more flexible solution, you could create a wrapper script:

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# run_stepwise_tests.py
#!/usr/bin/env python
import os
import sys
import pytest

if __name__ == "__main__":
    # Set Django settings module
    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "your_project.settings")
    
    # Build arguments
    args = ["--stepwise"]
    
    # Add any test labels passed to the script
    args.extend(sys.argv[1:])
    
    # Run pytest with the arguments
    sys.exit(pytest.main(args))

Then run it with:

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python run_stepwise_tests.py path/to/tests

Using pytest-django Plugin Features

The pytest-django plugin provides additional options that might be helpful:

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pytest --ds=your_project.settings --stepwise --reuse-db

The --reuse-db option is particularly useful as it speeds up test runs by reusing the test database instead of recreating it each time.

Remember that pytest's stepwise functionality stores information about the last failing test in a cache file, so it will pick up where you left off in subsequent runs, making the debugging process more efficient.